There is a group of words in the English language that are "uncountable" - in order to count them, you have to use a "counter". Food is one of them. Water, juice, wood, air are others.

In order to count these things (and make them singular or plural), they either have to be grouped into some countable "container" (baskets of food, glasses of water or juice, canisters of compressed air etc.), or you can use the words "some", "much" to describe them.

The way to find uncountable nouns is to see if you can "count" them without any other "container" between the number and the item:

"One cake""Two Cakes" - this word is countable

"One wood""Two woods" - not really. It would be better to say "One piece of wood". This word is uncountable.

"Foods" can be used when referring to different kinds of things, but it is a much less common usage.

I will write my doubt here, since is similar: it is regarding the plural and the singular of the noun.So I mean the noun "fish" - did I read that it is uncountable, whether it has the plural? I can see sometimes the word " fishes" in the text - whether it is the correct plural from the word "fish", whether it doesn't have plural form?